I have been using Adsense since 2012, however, I still get rejected whenever I submit a new site. It was easy in the past but these days getting approved for Google AdSense is not easy. Even when your site has a lot of original content, there's no guarantee AdSense will give you the green light. Adsense wants well-written content, but even if your website content is well written, there is no guarantee that Adsense will approve. Your website should also cover topics that aren't already all over the internet. If your website has the content on the topics that is saturated on the internet, AdSense might say no.